Mouthguard



FIG. 1 is a front, left side perspective view of a mouthguard showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof; and,

FIG. 8 is a rear perspective view thereof

The broken lines depict portions of the mouthguard in which the design is embodied that are not considered part of the claimed design. 

CLAIM The ornamental design for a mouthguard, as shown and described. 